Functional Diversity Based on Morphometric Analysis and Identification of the Algerian Carob Tree (Ceratonia siliqua L.) Cultivars

Abstract

Sixty-six carob accessions from 19 sites throughout Algeria were analysed by leaf, pod and seed characteristics to assess their genetic diversity and identify the first Algerian carob cultivars that could be used as germplasms for breeding programmes. We compared Algerian accessions with carobs from different Mediterranean countries, and our results showed a high level of morphological similarity between Algerian and Spanish carob pods. Analysis of variance showed highly significant differences (p ˂ 0.001) between accessions for all the quantitative traits. Correlation analysis between variables indicated that seed yield could be improved by selecting light, thin and narrow carob pods. Multiple correspondence analysis explained a total variance of 30.22 % and illustrated three distinct leaf classes. Principal component analysis proposed two main groups of variables, one based on seed performance and the other targeting pod potential. Hierarchical classification with seven clusters revealed considerable genetic diversity among the Algerian carob accessions studied, and indicated that the type of bioclimate did not influence their distribution, suggesting that morphometric traits are probably controlled more by genes that by bioclimate. Linear discriminant analysis, clustering and heatmap plotting identified 11 potential cultivars, 10 female and one hermaphroditic.